No clear answer, largely depends on the manufacturer BIOS implementation whether or not to accept/allowed the use of 1.5volt DDR3. Even if the BIOS allowed, the 1.5volt DDR3 ram module might not work correctly in under-voltage of DDR3L electrical specification.
You can try though, no actual harm using 1.5volts DDR3 on the lower voltage DDR3L ram slot.